1. Field of the Invention
The present invention relates to a transparent film scanner having a light source system with a diffuser and a reflector for scanning transparent films.
2. Description of the Related Art
The closest prior art of which the applicant is aware is disclosed in U.S. Pat. No. 3,850,523 to Skavnak, filed on Jul. 13, 1973, entitled by xe2x80x9cPHOTOCOPIER LIGHT BOXxe2x80x9d.
In scanning a transparent film or a transparency in a scanner, the transparent film is placed over a glass window. The light source is located over the film to be scanned. The transmitted light through the film is sensed by an optical sensing system placed underneath the window.
A traditional optical system for scanning a film is shown in FIG. 1. A film P1 is placed over a glass window G1. The lighting L1 for scanning the film P1 is a secondary light originated from a light source 10 and reflected by a reflecting plate 12. The optical sensor for sensing the light transmitted through the film P1 is located underneath the glass window G1 (not shown). The purpose for using a secondary light to scan the film is to obtain uniform light intensity.
The drawback of such a design is that the distance A1 between the reflecting plate 12 and the film P1 must be placed far away from the reflecting plate to obtain uniformity in light intensity. Such a structure increases the size of the scanner and is undesirable.
An object of this invention is to provide uniform illumination of a transparent film for a scanner.
Another object of this invention is to reduce the size of a scanner.
These objects are achieved by inserting a light diffuser in front of the light source. The diffused light is then reflected by a reflecting plate to illuminate the film placed on top of a glass scan window. When the light is thus diffused, the distance between the reflecting plate and the film can be made shorter than that in a traditional film scanner.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.